So-called spotting scopes (also known as finderscopes) are examples of object finders which may be used in conjunction with primary (typically high-magnification) optical instruments. By way of non-limiting example, such primary optical instruments may include telescopes (e.g. in the field of astronomy), surveying instruments and/or the like. Spotting scopes function as object finders and permit users to quickly find target object(s) to be observed by looking through the spotting scope. Typically, a spotting scope has a relatively wide field of view in comparison to the high-magnification primary optical instrument with which the spotting scope is used, so that it is relatively easy to locate target objects using the spotting scope in comparison to the high-magnification primary scope. When used in conjunction with a telescope, a spotting scope is typically mounted to the telescope. The optical axes of the telescope and spotting scope may then be aligned to be parallel with one another, so that the fields of view of the spotting scope and the telescope are oriented in the same direction. In use, a user first uses the spotting scope as an object finder by looking through the spotting scope and moving the combination of the spotting scope and the telescope until the target object(s) are located in the relatively wide field of view of the spotting scope. While continuing to look through the spotting scope, the user then moves the combination of the spotting scope and the telescope, such that the target object(s) are located approximately at the center of the field of view of the spotting scope. When the spotting scope is properly mounted (aligned) with the telescope and the telescope is positioned in this manner using the spotting scope, the target object(s) will be located at least approximately at the center of the field of view of the telescope.
Spotting scopes may also be used as object finders to manually correct errors associated with so-called “auto-tracking” telescope systems. As is well known, the rotation of the earth about its axis causes celestial objects observed from the surface of the earth to appear to move across the sky. An auto-tracking telescope system automatically orients its telescope to track the movement of a target celestial object, such that the target celestial object appears to stay at the center of the field of view of the telescope. Auto-tracking telescope systems typically depend on user input information (e.g. the time and date at the observer location, the geographical coordinates of the observer location and telescope axial references (e.g. a reference to true north and a reference to the horizon)). Such user input information may be measured and/or directly input by a user. Because this user-input information may have errors and/or because of other inaccuracies, auto-tracking telescope systems may exhibit tracking errors (where the target celestial object moves away from the center of the field of view of the telescope), particularly over extended periods of observation. Spotting scopes can be used as object finders by users to quickly re-center the target objects in the center of the field of view of the telescope, so that auto-tracking may resume with the target object(s) in the center of the telescope field of view.
Current spotting scopes are designed to find and observe particular types of target objects. For example, an existing spotting scope designed to find distant stars cannot be used to observe the sun without the potential for causing damage to the eye of the observer.
There is a general desire for versatile techniques for locating objects so that objects may be viewed using high-magnification optical instruments (e.g. telescopes, surveying instruments and/or the like).